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Free keywords:
Cognitive disorders; Language; Laterality; Magnetic resonance imaging; Motor activity
Abstract:
Background
—General conclusions concerning mechanisms of cerebral lateralization may be learned from the investiga-
tion of functional brain organization in patients with anomalous lateralization.
Case Description
—The functional organization of language, attention, and motor performance was investigated in a
42-year-old patient with crossed nonaphasia by means of functional MRI. The strongly right-handed man experienced
a left middle cerebral artery infarction documented by MRI without exhibition of aphasia. However, the left hemispheric
stroke was accompanied by visuospatial impairment, right-sided slight sensory and motor paresis, and right
homonymous hemianopia. No history of familial sinistrality or prior neurological illness was present. Functional MR
language mapping revealed strong right hemispheric activation in inferior frontal and superior temporal cortices. Finger
tapping with the right hand recruited ipsilateral premotor and motor areas as well as supplementary motor cortex. A
Stroop task, usually strongly associated with left-sided inferior frontal activation in dextrals, resulted in strong right
hemispheric frontal activation.
Conclusions
—From our data there is clear evidence that different modalities, such as language perception and production,
attention, and motor performance, are processed exclusively by 1 hemisphere when atypical cerebral dominance is
present.
